Hidrogeologia da faixa costeira de Aquiraz-CE

Abstract

This dissertation deals with the hydrological study of the coastal region of Aquiraz county, Ceará State, Brazil, where consumption of underground water corresponds to over 90% of the human population’s uptake. The research work has been undertaken on the basis of gathered bibliographic information, data on registered wells, chemical analyses and physiographic aspects. Geologically, the study area is represented by sedimentary rocks of the Barreiras Formation and by dune and alluvial deposits. Those rocks make up the porous media where there have been identified three occurrences of aquiferous fields of action, represented by the systems: Barreiras, dune/paleodune and alluvion. The alluvion’s water is considered improper for human consumption because of problems with its salinity. The Barreiras and dune/paleodune systems are ameable to exploitation because of favourable hydrological and lithological conditions, the latter having comparatively a more important resource potential than the former, whose silt-clay intercalations make it less permeable. The aquiferous systems are fed by rainfall, which is accountable for variations in the underground reserves and the water balance. The qualitative analyses show that most of the underground water can be chemically classified as of good quality, whereas from a bacteriological viewpoint this does not hold true because of defficiencies in the water sewage system.